Areas of Morphological Erosions
Computes the areas of successive morphological erosions of a window.
eroded.areas(w, r, subset=NULL)
w |
A window. |
r |
Numeric vector of radii at which erosions will be performed. |
subset |
Optional window inside which the areas should be computed. |
This function computes the areas of the erosions of the window
w
by each of the radii r[i]
.
The morphological erosion of a set W by a distance r > 0 is the subset consisting of all points x in W such that the distance from x to the boundary of W is greater than or equal to r. In other words it is the result of trimming a margin of width r off the set W.
The argument r
should be a vector of positive numbers.
The argument w
should be a window (an object of class
"owin"
, see owin.object
for details)
or can be given in any format acceptable to as.owin()
.
Unless w
is a rectangle, the computation is performed
using a pixel raster approximation.
To compute the eroded window itself, use erosion
.
Numeric vector, of the same length as r
,
giving the areas of the successive erosions.
Adrian Baddeley Adrian.Baddeley@curtin.edu.au
and Rolf Turner r.turner@auckland.ac.nz
w <- owin(c(0,1),c(0,1)) a <- eroded.areas(w, seq(0.01,0.49,by=0.01))
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